Process for extracting metals from their ores.



H. S. MAGKAY. PROCESS FOR EXTRACTINB METALS FROM THEIR DEBS.

APPLIGATIOH FILED JAN. 20 1910. 1,01 1,459.

Patented Dec. 12, 1911.

4 SHEETBBHBET 1.

H. S. MAGKAY.

PROCESS FOR BX'IBAOTING METALS FROM THEIR 0115s.

1 1 9 1 2 1 G e D m n e .T a P. 0 1 9 0 2 K A D B Yu L F H 0 I T A 6 TB L P P A 4- BHEETS-SHEBT 2 m I n I I a I u 7 u I n I I I I u {1 k 1 I I!ddlldrllllflllrrlfllrfil Aw Attorney H. S. MAUKAY.

PROCESS FOR EXTBACTING METALS PROM THEIR ORBS.

APPLIGLTIOH rum) JAN. 20, mo.

1,01 1,459. Patented Dec. 12, 1911.

4 SHEETS-SHEET 3.

H. S. MAGKAYI PROCESS FOR EXTBACTING METALS FROM '1 HEIR 0112s.

Patented Dec. 12, 1911.

4 s'nns'rs-sann'r 44 4 j rtfffl.

APYLIUATIOH TILED 11111.20, 1910.

UNITED STATES PATENT OFFICE.

HENRY S. Mac-KAY. 0F RIVERSIDE. CALIFORNIA. ASSIGNOR T0 MACKAY COPPER PROCESS COMPANY. OF RIVERSIDE, CALII'TORNIA, A CORPORATION OF ARIZONA TERRITORY.

PROCESS FOR EXTRACTI NG METALS FROM THEIR. ORES.

Specification of Letters Patent.

Patented Dec. 12, 1911.

Application filed January 20, 1910. Serial No. 538,560.

To all whom it may concern:

Be it known that 1, lluxnv S. .\l.\cl.\v. a citizen of the l'nited States. and a resident of Riverside. California. have invented a certain new and useful Improvement in Processes for lLvtrau-tiue Metals from Their I when first used. The-metal may he removed from the orehy means of a solution'eontaining the active agent or agents and then the agent or agents may he separated chemically from the metal and at' the same time they may be liheratedinto the solution "in an active relationship or condition. The solution may thus he revived to its former chemical strength. Also if desired the. nietal may be returned from the revived solution immediately upon its separation from the active agent or elements. 7

In the accomplishment of the preferred form of the invention on the preferred -metho'd involving the use of the invention one or more active elements. are produced in a solution and brought into contact with the ore. The ore is thoroughly treated with the solution giving the a ents an opportunity to attack the metal 0 the ore andproduee a soluhlesalt. The valuable metal is then removed from the solution formed after the agents have chemically united with the metals of the ore. The solution is revived by freeing the agents from the desired metal into the solution which restores the solution to its solvent; power. At the. same time that the solution is revived the metal is removed from the part of the solution containing the regenerated or newly freed agcnts to a ,llQH-tlCtlVt! solution or a non- 4 active or saturated or satisfiethportion of the solution. This prevents subsequent ac 'tion of the agents on the metal. Successive tion of copper from its ore.

charges of the ore are thus treated by the constantly revived solution.

For the purpose of illustrating the application of my invention and to show that it is practical I shall descrihe a process involvin; the use oi the invention for the ex rac l shall also descrihe a means for caruviug out the process.

The process may he greatly modified and used for the-extraction of many metals and vet such modifications of the process will still contain the essence of the invention.

teferriug to the drawings. Figure 1 illustrates a side view of one forurot apparatus that may'he used in carrying out the process which I am ahout to descrihe. Fig. 2 illustrates a top view of such an apparatus. Fig. 25 illustrates a side secti nal view of two electrolytic vats. ljig. 4 illustrates a top view of lhe. vats. Fig. 5 illustratcs an end sectional view of one of the vats. Fig. (3 illustrates a mixer used in connection with the apparatus. Figs. 7 and 8 illustrate side sectional and top views of another electr lytic vat.

Referring to Figs. 1 and 2. is a re ervoir for containing a solution of a salt of an alkaline metal which is used in the production of the active agents. 1-, and are the electrolytic vats for treating the solution. In B the solution received from is treat d and in C the solution received from B is likewise treated. I) is a reservoir which receives the prepared solvent. from the vats. E is an agitator in which the charges of the ore are placed and then treated with the solution prepared in the vats B and or with the revived solution formed after the charges of the ore have been leached. F is an electrolytic vat in which the metal is re moved froin the solution received from the tank E. At the same time that the metal is taken from the. solution the solution is re vived so' that it can he .used again for the extraction of metal from the. ore. (l is a reservoir which receives the regenerated solution from the electrolytic vat F. It is a suitable pump which transfers the revived solution from tank G to tank D. a is a. pipe used to convey {isolation from the reservoir A to the electrolytic vat B. t are pipes usedv to convey solution from vat B to at C. u are pipes used to convey solution from vat C ti U 5 used for conveying solution from the vat F to the tank G. f is a pipe or launder used to convey the copper precipitated in the electrolytic vat F to the tank H and y is a pipe through which the regenerated solution is discharged from the tank G into the tank 12 1s a pipe which conducts a solution formed in vat C to a tank 14.

The solution for treating the ore may be prepared by forming an aqueous solution of 15 a salt, such as common salt (sodium chlorid) in the tank A. This solution may be prepared by either dissolving the salt in water or by evaporating sea water until the water carries the proper percentage of sodium chlorid. Some natural waters, such as the salt water from the Salt Lake pf Utah, may be used withoutaddition or removal of salt. The aqueous solution of sodium chlorid'is directed into the electrolytic vat B, shown in Figs. 4 and 5, until it is filled. The vat B is provided with diaphragms 7; p made of suitable porous material that will allow electrolytic action in the vatl The diaphragms form cells or compartments in w ich the electrodes are placed. The cathodes are placed in one set of cells and theanodes are placed in another set of cells- The cells having the cathodes alternate with the cells having the anodes, a pair of cathodes or a pair as of anodes being placed in'each cell, except in the first and the last cells, in which single anodes or cathodes are placed.

n are the cathodes and n are the anodes. The anodes 11 may be formed of a metal 40 which will in the process react or cooperate with the solution to produce the active agents which extract the des red metal from the ore: In this particular rocess the anode is made of'iron. The catiodes n may be made of an insoluble material.

K and J are electric conductors: which carry a currentof electricity to and, from the electrodes n and n. K is a conductor which is connected. with the cathodes 'n'; J

is a conductor which is connected with the anodes n, the anodes and cathodes being connected in parallel. The current passes into the electrolytic vat-s through the conductor J to the anodes n and through the solution surrounding them and the diaphragms p and p to the cathodes n and to the conductor K and back to the generator.

Passing an electric current through the solution of sodium chlorid in the presence of iron or similar material results in the decomposition of the sodium chlorid and dissolution of the metal of the anode. The sodium of the salt and hydrogen of the water are liberated at the cathodes. They are deposited or liberated in the solution of the cells containing the cathodes while chl0- rin and oxygen are liberated in the solution about the anodes. Chlorids of the anode metal are thereby formed and some free chlorin remains in the solution about the anodes. The result of the chemical reaction and electrolysis will be the formation of ferrous and ferric chlorids by some of the chlorin combinin with the iron. If the current is continued For a sufiicient length of time all the chlorin contained in the solu-v tion will pass to that part .of the solution surrounding the metallic anodes. The sodium is deposited in thecompartments which contain the cathodes and it there decomposes the water of the solution and forms caustic soda. The iron dissolved in the anode solution, being an clectronegative element, is partly transferred to the oathodes but as fast as it is transferred,-it is preci 'itated in the compartments of the cath- 0 es by the caustic soda formed in the oathode solution and falls to the bottom of the compartment. But as the iron of the anode dissolves faster than it can be deposited at the cathodes, the surplus chlorid of iron is retained in the anode compartments. After sufficient chlorin and chlorids of iron for the required purposes are formed in the anode compartments the current is turned off and the solution is allowed to flow into another electrolytic vat C. The vat' C is constructed the same as vat B and the solution of the compartments containing the anodes of vat B is directed into the-compartments containing the anoclesiof the vat C. The same is true of the solution contained in the compartments of vat B in which the cathodes are located which is directed into the corresponding compartments of vat C. The anode compartments of vat C thus receive the ferrous and ferric chlorids and free chlorin in solution while the cathode compartments receive part of the original sodium chlorid solution and some caustic soda. in solution. The object in changing the solution from one vat to the other is to convert all the chlorid in the anode-divisions from the lower chlorid to the higher, in this case to ferric chlorid and produce free chlorinbut this object can be obtained by inserting insoluble anodes in place of the soluble anodes instead of changing the solution as above described. Furthermore the solution may flow continuously from one vat to the other while the electrolysis is'going on, the fluids being at the same time removed from the second vat. The solution about the cathodes win the vat B is directed into, the compartments containing the cathodes n of the vat G and the solution about the metallic anodes n is directed into the compartments about the insoluble anodes 1 in vat C. After the solution, or the anodes, has been changed and the electric current has been turned on,the current will pass from the insoluble anodes 1 through the pornus diaphragms nd the solution to the cathodes n and then back to the generator. In the conrseofthe electrolysis sodium and hydrogen are deposited at the cathodes and ehlorin and oxygen at the anodes. Part of the chlorin and the hydrogen which collects at the top of the plates may, ifdesired, be united to form hydrochloric acid. Also some sodium chlorate is formed by the action of the chlorin. The ferrous chlorid formed in vat B is changed into ferric chlorid. When all the ferrous clzlorid is converted into ferric chlorid the preparation of the solvent is finished. The anode compartments then contain ferric chlorid and free ehlorin in the solution and if the vat is covered or sutlicient lightis given, they will also contain hydrochloric acid. The solution from the anode compartments g, g is then directed into the tank I) and the solution of the cathode compartments is directed intoa separate tank 14. When a sufficient quantity of a solvent is prepared theore is treated with it. The ore is placed in an agitator E. The ore is pulverized -and the tank is partly filled therewith. The solution is drawn from the reservoir I) and directed intoihe tank E until the ore is submerged. One part of the solution by weight to one part ore to two parts solution to one part ore is used as may be desired varying the proportions according to the fineness to which the ore is crulsched and the texture and character of the roe Fig. 6 illustrates quite in detail the construction of oneform of agitator. 15 is the wall of the tank which may he made of any non-metallic substance, which will not be acted upon by the acids of thesolutionnsed in leaching the ore. E is a filling which forms a conical bottom for the inside of the tank. X is a central tube. \V is a movable lloat surrounding and adapted to move along the central tube X. The float is cup-shape and is adapted to decant the clear solution from the ore as needed. A cover Z is located a short distance above the float and is adapted to protect it. from the spray formed at the top of the tube X. :r is an.

air pipe connected with a reservoir or pump having air under pressure. The air pipe extends up a short distance into and along the 0 mixture'of the ore and solution in the tank.

is the top of the solution whicheovers the 5 ere. 0 isthe top of the tank. 0' is a discharge gate at the bottom of the tank. 3 are supports for the.tauk which hold it above the flooring so as to leave a clear space in order that the tailings may be conveyed away from underneath the gate 0.

After the ore and solution have been placed in the agitator E, air under pressure passes in at the pipe as and up the tube X forcing with it the crushed ore and solution which enters the central tube at its lower end. The mixture comes in contact with the deflector Y and is thrown to the outer walls of the tank. .The lower end of the tube X is laced at the center of the conical bottom ot the tank and as the mixture settles it is drawn in at the bottom of the tube X aiul'carried upward to the deflector from whence it is returned down the sides of the tank making a continuous operation as long as air under pressure is passed through the pipe The ore in the tank is thus thoroughly leached with the solution. It is often necessary to agitatethe ore while leaching it audit is preferable to do so to save time but thesolvent under certain. conditions will dissolve the copper from the ore without agitation,- Vhen the ore is leached in the solution for a sufficient tiine to allow the ferric cl'ilorid and the chlorin and the chlorin acids, that is, the active elements in the solution, to form chlorids of the metals in the ore, the solution is drawn olt and a new solution added if necessary until all the copper is reduced to a chlorid. The solution is drawn oil by decanting the clear soluthrough the tub w and through the valve 4 and pipe in which leads to the electrolytic vat t In the leaching process, iii-the ore contains copper and another metal, and if an anode of the other metal is used in-the preparation of the. solvent such as iron, etc., the so-.; lution carrying potentially active chlo'ril'l elements, such as the higher chlorid of the said thermetal such as ferric chlorid and free chlorin, and chlorin acids such'as h v drochloric acid-and sodium chlorate, give up :1 art of the chlorin. In the process j ustdescrlbed which is illustrative of one form of the invention, the ferric ehlor'id is reduced to ferrous chlorid, some of its chlorin being liberated, and the free chlorin thus.

liberated and the chlorm in the solution and chlorid in solution is allowed to remain in contact with the ore, it will in; turn attack the copper of the ore and form cuprous chlorid thereby takin out an additional 9 amount of the copper l rom the ore. \Vhen the chlorids of the metals of the ore are formed the solution is drawn oil'and the charge of ore may be again treated with another charge of the solution containing the elements in active relationship unless all of the copper is removed from the ore. Until this occurs the ore is leached with charges of the solution. \Vhen the copper is removed another charge of the ore is treated with the solution. The solution drawn oil' from the ore is directed into the electrolytic vat F and the copper is removed by electrolysis. It may be separated from the solution on the cathode either in the form of copper plate or as spongy copper in a powder condition, according to the strengt of the current used. At the same time that the copper is separated from the solution the chlorm with which it was combined while in solution is restored to substantially its ori inal potential chemical relationship in t e solution. The ferrops 'chlorid is chan d to ferric chlorid, free chlorin is restored to the solution and hydrochloric acid is formed if de sired, the same as in the original solution. The revived solution is then pumped back into the tank D to be used over a in. Some of the cuprous chloridmay stil remain in the solution but it is sooner or later removed in the successive treatment of the solution in the precipitating vat F.

The vat F has walls'madc of any suitable material which will notbe. acted upon by the electrolyte, or the agents produced in. the electrolysis.

5, 5 are the anodes which are made of an insoluble material.

6, 6 are the cathodeswhich may be made of either a. soluble material or an insoluble material but -are soluble material.

J is the main conductor carrying the current to the anodes 5 and K is the return conductor which connects the cathodes 6 with the generatorp The electrodes of the vet are thus connected in multi le. In the arrangemerlt shown both side of the cathodes and anodes are available the anodes and the cathodes being located alternstely in makin up the cell. he current passes mthroug each anode to the opposing cathodes located on opposite sides of the anode. exoept'the first and last anode or cathode'w ich each case but one opposing surface.

space I between the bottom of the vet and the lower ends of the electrodes. This space 18 utilized for collecting the copper. The solution in the space I is not acted upon by. the

65 current and no active agents are ormed 'tously.

preferably made of an in-' settles to the bottom. Thesolution is have in- The vat F is so constructed that there is ,a

therein. It thus remains neutral or nonactive. The copper precipitated at the cathodes 1S collected in this portion of the solution.

The result of the electrolysis in the vat F I andjn the vicinity of the anodes with the result that the copper is deposited in the form of powder at the cathodes which procipitates to the bottom of the vat. Part of the hydrogen may be combined to form hvdro'ehloric acid while some of the free ehlorin remains in the solution. The solution below the electrodes, however, remains unchanged. In this condition it is new active and it will not dissolve the copper. When the ferrous chlorid is converted to thelerric ehlorid the current is turned oil. It is found by practical working of the rocess that by continuing the current for a onger period the ower of the solution to extract the copper om the ore is gradually destroyed for the ehlorin will begrsduslly liberated at the anodes. When the ferrous chlorid is converted to the ferric chlorid as above described, it; then contains free chlorin and activeehlorin com ounds and is in the best condition to be use over again as a. sol vent. The regenerated solution is then drawn through the pipes cl, d and returned -to the tank D through the tank G and the [pump 1:. and pipe y. It is again directed to tho-agitato ,for another operation and the solution produced after leaching is again directed into the vat F and so on circui- When the solution about the electrodes is removed, the part in the bottom of the vet; that-is, the portion more or less saturated with the salt of the metal obtained from the ore and which receives the copper is left in the bottom of the vat. When Sllillcient cop er'hss accumulated in the vet F and in t e solution below" the electrodes and after the solution about the electrodes has been drawn 05, the copper and the surrounding solution is drawn 6E through the pipe connections friend dirccted'to a. storage tenkor reservoir H wherc'the copper drawn of and returned to the-'vst'D and the copper is .placed in a. suitable and melted into the refined copper bars of commerce.

In the many experiments and practical tests that I have made with this recess it appears that the solvent produced s exceedingly eficient. However it is to be understood that I do not confine myself to the exact rocess or means specified herein for the p rosuction of the solution containing t active elements. A solvent may be preps ed m!- and the solution may be .revived upon the extraction of the copper contained in it as above described.

It is found after a long series of practical tests that the reactions that take place an der the above Conditions are substantially as specified, but whatever may be the reactions or whatever active agents may be pro-. duced in carrying out the process, the electrolytic reduction of copper from its ore. which has been selected for the purpose of illustration only, is accomplished by the steps described.

. The invention may be modified by those skilled in the art to which it pertains without departing from the spirit thereof. The

invention itself may be used in many chemical or electrolytic processesto accomplish many results, what I have described above being merely an illustrative process involving and containing the essence of the invention.

\Vhat I claim-as new and desire to secure by Letters Patent is as follows 2 1. A process of producing a solvent for orcsfwhich consists in decomposing a solution of a salt in contact with a soluble material and transferring the acid radical of the said salt from one part of the solution to another and electrolvzing the resultant solutionformcd after the transfer in consolution.

tact with an insoluble electrode.

2. A process o'E-treating ore ,wliich consists in electrolyzing a solution of sodium chlorid in contact with a soluble anode which will form a solvent for acting on the ore, electrolyzing the solution produced in the last mentioned step in contact. with an insoluble anode, leaching the ore with the solution produced in the last mentioned step, reviving the solution by treatment of the elements in the solution produced in the last mentioned site with the regenera solution.

3. A' recess of extracting metal from its ore, which consists in clectrolyzing a solution of a. salt in contact with a soluble metal anode which will form a. solvent for acting on the ore and then in contact with an in-. soluble anode, leaching the ore with the resultant solution, reviving the solution produced by the said leaching from the elements of the solution by electrolyzing the 4. A process of extracting metal from ore which consists in. electrolyzing a solution of sodium chlorid in contact with a metal anode which will form a solvent for acting on the ore, dissolving the anode metal in the The active chlorin,

and leaching the ore' solution and forming a solution of a lower chlorid of the metal and forming achlorin agent, leaching the said ore with the resultant solution, reviving the said solution after it has leached the said ore by treatment of the elements in'the solution, and producing the desired metal and then leaching another charge of the ore with the resultant solution.

5. A process of extracting metalliccopper from the ore, which consists in electrol vziiig a solution of sodium chlorid'in contact with soluble metallic anodes which will form a sotvent for acting on the ore, forming a solution of chloridof the said anode metal and converting the said clilorid to the chlorid of a higher order and at the same time forming another chlorin agent in the solution, leaching one charge of the ore with the resultant solution. reviving the solution from the leached ore by treatment of the elements in the solution and pi'oducin metalliccopper, and leaching another (large of the ore with the resultant solution.

6. A process of treating ore which consists in decomposing a solution of sodium chlorid in contact with a soluble metallic anode which will 'form a solvent for acting on.the ore, transferring the chlorin from one part of the solution to another, leaching the ore with the portion containing the chlorin. reviving the said solution by treatment of the elements in the solution-and leaching a' second iiantity of the said ore.

7. A process 0 extracting metal from ore, which consists in elcctrolyzing a solution of sodium elilorid in contact with a soloble metallic anode which will form a solvent for acting on the ore, electrolyzing the solution formed in the last mentioned etc in contact with an insoluble anode, leac ing the ore with the solution formed in the last mentioned step, reviving the solution formed in the last mentioned step by tpiaat- ,ment of the elements in the solution and producing the metal at the'same time from the said solution while it is being revived.

S. A process of extracting copper from its ore, which consists in electrolyzing a. so-. lution of sodium ,clilorid in contact with a. soluble metallic anode which will form in the solution a solvent of the cop er compounds of the ore, dissolving t e metal an iron anode, collecting the solution formed ore having two 'or more metals, which conabout theanode and again electrolyzin the sists in forming the chlorids of the metals said solution formed about the said ano o in of the ore other than the desired metal and contact with an insoluble anode, leaching'the electrolyzing the solution, precipitating the ore with the solution formed aboutthe 'mdesired metal and changing the chlorid com 70 soluble anode, electrolyzing a portion of the pound of the said other metal of the ore solution formed in'the lixiviation, precipithus formed from the ore to a chlorid of a tatingthe cop er; and collecting it in a sehigher order and treating another charge of ond portion 0 the'said solution and at thethe ore with a solution of the said chlorid same time recharging the first mentioned of higher order. 75 portionwith the active agents found in the 16. A recess of extracting metal from leaching solution and-again'leaching a secore, whic -consists in treating the ore with ond charge of the ore. an active agent in solution, preci itating the 10. A process of extracting a metal from desired metal into a non-active aid and re-. ore, which consists in electrolyzing a solustoring to the solution formed. after the so tion of sodium chlorid in the presence of a treatment, the active agcnt released in premetal which will form a solvent for acting cipitating the said metal. on the ore, and a ain electrolyzingthe solu- 17. A. process of extracting metal from tion"thus formed-in contact with an inore,whic consists in leaching the ore with soluble'electrode, leaching the ore with the an active agent in a solution,.precipitating 85 solution thus formed, eleetrolyzing the soluthe desired metal into a portion of the solutionproduced after leaching, precipitating, tion formed after leaching, and reviving the the desired metal into a part of the soluremainder of, the said solution formed after tion formed after leaching theore, and releaching by treatment'of the elements in the storin to another portion of the solution solution. 9o -for m after leaching of the ore the chlorl 18. A rocess of extracting copper from released from the desired metal. ore, whic consists in leaching the ore with A Process of e i g which m an active chlorin agent in a solution, presists in leaching a charge of the ore with a cipitating the copper into a portion of the so solution containing a metallic chlorid and solution formed after leaching, and restor- 95 free hydrochloric acidand reviving the ing the chlorin combined with the copper resultant solution produced afterdeachmg after leaching to the remainderof the said the ore by treatment of the elements in the solution from which the said copper is presolution and leaching another charge of the cipitated.

ore with the revived solution. -19. The recess of extracting copper from 100 12. A process of extracting me al from its ores,. w ich consists in leaching the ore its ores having two or more metals, which with a solution containing active chlorin consists in electrolyzing NaClin solution and agentsyelectrolyzing a portion of the soluforming hydrogen and chlorin which are tion-'fornied in the lixiviation, precipitating 40 permitted to unite in part to form hydra the copper and collecting it in a second por- 1 chlorie acid and treating the ore with the tion of the solution and at the same time solution thus formed and electrolysing the reviving th first mentioned portion with resultant solution and again forming HCl active chlorin agents, by treatment of the and a higher chlorid of one of the metals elements in the solution and again leaching in said solution and again leaching another the second ehar' e of the ore with the solu- 110 char e of the ore with the solution containtion thus forms ing e HCl and the higher chlorid formed 20. The recess of reducing copper from in the last mentioned step. its ores, w ich consists in leaching the ore 13. A process of treat ng ore having two with a solution of a chlorid of a metal of a V or more metals, which consists in leaching hi her order, electrolyzing a portion of the 1}? a char e of the ore with asolution containso ution formed in the lixiviation, precipiing ch orids of one or more of the metals of tating .the copper and collecting it in a the ,ore and changing the chlorid of a metal second portion of the solution and at the of theme other than the desired metal to a. same time recharging 'the first named porchlorid of that metal of a higher order and tion with a chlorid of a metal of higher leaching another charge of the ore with the order,- chlorin and hydrochloric acid and solution thusiormed. a ain leaching the. second charge of the ore 14. The process of extracting copper from with the last mentioned solution. its ore, which consists in making a solution 21. The process of treating copper ores 60 of thechlorids of the metals contained in havin iron, which consists in forming the the ore and electrolytically precipitatin the chlori of the metals with a chlorm agent, 00 per and charging the ,chlorids o the decomposing the chlorid of copper from a ct er metals with the ehlorin from the metal portionof the solution thus formed and recipitated. precipitating theflcopper into another per- 46 15. The process of extracting metal from tionof the solution thus formed and at the 1 same time forming chlorid compounds of the iron in the first, portion of the solution and treating another charge of the ore.

22. A process of extracting metal from ore, which consists in elcctrolyzingasolution of sodi'unrchlorid in the presence of a metal which will form a solvent for acting on the ore, leaching the ore in the said solution by treatment of the elements in the solution and cleetrolyzing the solution formed after leaching, and precipitating the metal into a portion of the said solution formed after leaching.

23. A process of extracting a metal from its ore, which consists in leaching the ore with a'solution having active agents and reviving the compounds formed by the action of the said active agents on the metals contained in the ore by treatmciit of the elements in the solution and at the same time precipitating the desired metal into a part of the solution unrevived and leaching an- Qther charge of the ore.

24. A process of extracting metal from ore having two or more metals by leaching 2 the ore with a solution of an active agent, which metals other than the desired metal will constitute a medium for the retention of the said active agent and charging the said medium with the active agentcombiucd with the desired metal in the leaching step and leaching another charge of the ore with the resultant solution, thereby obtaining an additional amount of the metal other than the desired metal for the retention of the 3 active agent: until the compound of the said solution becomes concentrated to a more or less degree with the said other metals.

. In testimony hereof, 1 have signed my name to thisspecitieation, in the presence of 4 two subscribing witnesses.

llIGNlt Y S. MAcKAY.

\Vitnesses: F. F. (Inuit-Ton, M. A. liu'ruau. 

